SSH免密无法登录

时间：2025年8月8日

记录一次SSH免密无法登录处理过程

现象

提交git仓代码时发现需要输入密码，检查git公钥私钥正常，怀疑gitea bug，删除gitea账户的密钥后，仍失败

排查过程

1、查看本机密钥权限是否存在异常

root@VM-2-16-ubuntu:~/.ssh# ll
total 24
drwx------  2 root root 4096 Aug  7 23:56 ./
drwx------ 25 root root 4096 Aug  7 23:51 ../
-rw-------  1 root root  777 Dec 13  2024 authorized_keys
-rw-------  1 root root  411 Nov 19  2024 id_ed25519
###权限正常600 -> 411
-rw-r--r--  1 root root  101 Nov 19  2024 id_ed25519.pub
-rw-r--r--  1 root root  142 Aug  7 23:56 known_hosts

2、查看本机公钥私钥是否匹配

root@VM-2-16-ubuntu:~/.ssh# cat id_ed25519.pub 
ssh-ed25519 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA root@VM-2-16-ubuntu

ssh-keygen -y -f ~/.ssh/id_ed25519
ssh-ed25519 AAAAAAAAAAAAAAAAAAAAAAAAAA root@VM-2-16-ubuntu

###密钥结果匹配，本机无异常

3、查看本机debug日志

root@VM-2-16-ubuntu:~/.ssh# ssh -vT -i ~/.ssh/id_ed25519 git@git.lzcwy.cn
OpenSSH_9.6p1 Ubuntu-3ubuntu13.5, OpenSSL 3.0.13 30 Jan 2024
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to git.lzcwy.cn [82.157.64.204] port 22.
debug1: Connection established.
debug1: identity file /root/.ssh/id_ed25519 type 3
debug1: identity file /root/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_9.6p1 Ubuntu-3ubuntu13.5
debug1: Remote protocol version 2.0, remote software version OpenSSH_9.6p1 Ubuntu-3ubuntu13.13
debug1: compat_banner: match: OpenSSH_9.6p1 Ubuntu-3ubuntu13.13 pat OpenSSH* compat 0x04000000
debug1: Authenticating to git.lzcwy.cn:22 as 'git'
debug1: load_hostkeys: fopen /root/.ssh/known_hosts2: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts2: No such file or directory
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: sntrup761x25519-sha512@openssh.com
debug1: kex: host key algorithm: ssh-ed25519
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: SSH2_MSG_KEX_ECDH_REPLY received
debug1: Server host key: ssh-ed25519 SHA256:KeQo88NlFRuNnUykhPUh2o0dyWazhH9OIvIPklUD4w4
debug1: load_hostkeys: fopen /root/.ssh/known_hosts2: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts2: No such file or directory
debug1: Host 'git.lzcwy.cn' is known and matches the ED25519 host key.
debug1: Found key in /root/.ssh/known_hosts:1
debug1: ssh_packet_send2_wrapped: resetting send seqnr 3
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: Sending SSH2_MSG_EXT_INFO
debug1: expecting SSH2_MSG_NEWKEYS
debug1: ssh_packet_read_poll2: resetting read seqnr 3
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey in after 134217728 blocks
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_ext_info_client_parse: server-sig-algs=<ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ssh-ed25519@openssh.com,sk-ecdsa-sha2-nistp256@openssh.com,rsa-sha2-512,rsa-sha2-256>
debug1: kex_ext_info_check_ver: publickey-hostbound@openssh.com=<0>
debug1: kex_ext_info_check_ver: ping@openssh.com=<0>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_ext_info_client_parse: server-sig-algs=<ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ssh-ed25519@openssh.com,sk-ecdsa-sha2-nistp256@openssh.com,rsa-sha2-512,rsa-sha2-256>
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Will attempt key: /root/.ssh/id_ed25519 ED25519 SHA256:w2mqdrO/ZGBBofMzBXHkEIyuoSudfgtF3rTr5Tlr6eE explicit
debug1: Offering public key: /root/.ssh/id_ed25519 ED25519 SHA256:w2mqdrO/ZGBBofMzBXHkEIyuoSudfgtF3rTr5Tlr6eE explicit
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: password
git@git.lzcwy.cn's password: 

###debug1: Offering public key: /root/.ssh/id_ed25519 ED25519  说明本机可以识别到密钥并正确发送，查看对端日志

4、查看对端ssh日志

root@VM-24-13-ubuntu:/home/ubuntu# tail -f /var/log/auth.log

2025-08-07T23:50:16.251031+08:00 localhost sshd[553036]: User git not allowed because account is locked

###账号被锁定了

5、查看账号状态

root@VM-24-13-ubuntu:/home/ubuntu# passwd -S git 
git L 2024-12-31 -1 -1 -1 -1

###L为被Lock，解锁账号

6、解锁账号恢复

usermod -p 密码 git

5.1 KiB Raw Blame History Unescape Escape

SSH免密无法登录

现象

排查过程

5.1 KiB

Raw Blame History